An Andy Warhol portrait of Chinese Communist Party founder Mao Zedong has been sold at a historic auction for $US12.6 million ($16.5 million) in Hong Kong.

It is the first time one of Warhol's works depicting the founder of the communist leader has been auctioned and sold in a Chinese territory.

Previously, Chinese officials had stopped versions of the painting being exhibited in its territories, where censors closely guard Mao's image.

The painting, simply titled "Mao", was sold to a private Asian collector at a Sotheby's auction — it sold for much less than the $US15 million ($19.7 million) it expected to fetch.

The portrait was last on sale three years ago in London and its value has since increased nearly 20 per cent.

Sotheby's Asia Chairman Patti Wong said there was continual interest in western art by Asian buyers.

Warhol began his series of silk-screen portraits of Mao in 1972, when ties between then-Cold War foes China and US began to thaw after the historic trip to Beijing by former US president Richard Nixon.